Illuminated display device



Y'paneland the sourceY of `ultraeviolet light. tlcularly .truein the case of the application of various 'United States Patent ILLUMINATED DISPLAY DEVICE 4Edgar A. Lundberg, Park Ridge, and'Willson A. Spielmann, Winnetka, Ill., assignors to fl'he Tablet & Ticket Co., Chicago, Ill., a corporation of Illinois ApplicatienfNovember 26, 1954, Serial/No. 471,416 2 Claims. ((11.40-135) The'present invention is directed to an improved illumi- .natedv display device, and has particular reference to illuminated directory panels of the type used as building directories.

The present invention provides an improved directory panel in which suitably engraved strips are illuminated by a uniformly diffused fluorescent surface which, in turn, receives its energization from a source of ultra-violet light.

Previous attempts to provide illuminated directories of vthe type described withan ultra-violet or a so-called black light source .have not always proven successful. A major problem .in this regard has been the proper `application of the fluorescent surface between the viewing This is parlluorescent paints to strips composed of resin impregnated paper. In such cases, the fluorescent coating apparently is capable of readily impregnating the resin coated paper composition, with the result that the light transmitting characteristics of the panel strips were considerably modified. This frequently resulted in the inability to provide a sharp contrast between the engraved portions of the panel strips and the portions which were supposed to be completely light impervious.

Beside the undesirable changes in the light transmitting characteristics, the application of fluorescent paints to panel strips of this type seemed to accentuate the tendency of these strips to warp. These strips have a natural tendency to deform quite readily even at only moderately elevated temperatures, so that the additional warping effect provided by the presence of the iluorescent paint was completely undesirable.

In addition to the foregoing, in the illuminated directories of the past, it has not always been possible to provide a visible light of uniform intensity at the face panel, so that undesired high-lights and low-lights were presented at the front of the panel.

With the foregoing in mind, an object of the present invention is to provide an improved illuminated display device which presents a viewing panel of clearly defined high-lights set olf by a completely light impervious background.

Another object of the invention is to provide an improved illuminated directory activated by a source of ultra-violet radiation, with means being provided to transform the ultra-violet radiation into a visible light source, and to dilfuse this visible light substantially uniformly along the viewing panel of the directory.

Another object of the invention is to provide an improved illuminated directory with a light diffusing means which also serves as a mechanical support for the replaceable name strips contained in the front panel of the directory.

Other objects and features of the present invention will be apparent to those skilled in the art from the following description taken in connection with the attached sheet of drawings which illustrates a preferred embodiment of the invention.

, 2,825,164 Patented Mar. 4, 1958 a substantially rectangular frame including a pair of opposed side `rails .11 and'12, and a pair of end rails 13 and 14 at oppositeends thereof, the end rails 13 and 14 being removably secured to the ends of the side rails 11 and 12.

The side rails `llandy -12are generally L-shaped and areeach providedwith a longitudinally extending groove 15 and 16, respectively, Vextending'the fullheight of each of the side rails.

The depth of the grooves 15 and 16 is sufcient to receive vboth 'a glass plate-19 which forms the outside surface of the illuminated panel, and a plurality of resilient-strips 20. The structure of the strips 2i) will be discussed more completely in a succeeding portion of this description.

The bottom rail 14 is provided with a pair of pins 21 which serve to locate a backing member such as a coated glass plate 22 snugly against the rear surfaces of the strips 20.

The unit assembly consisting of the frame, the outer glass plate 19, the strips 20, and the backing glass plates 22 forms the front panel of the directory structure, the remainder of the structure including a shell-like housing 23 which contains a source of ultra-violet light, such as an elongated ultra-violet tube 24. The tube 24 is received between sockets 25 arranged to be energized by means of a conductor 26 from a suitable source of electrical current.

The illuminated panel of the device is detachably secured to the housing 23 by providing a pair of spaced lugs 27 on the opposed side rails 11 and 12, the lugs 27 serving to anchor one end of each of a pair of coiled springs 28. The opposite ends of the springs are formed with a bent hook portion as indicated at 28a arranged to be received in apertures 29 formed in the housing 23.

When the ultra-violet tube 24 is energized, it emits radiation which for the most part is in the invisible ultraviolet range. This radiation is reilected to a large extent from the angular surfaces of the housing 23. To prevent the production of unequal light striations, the backing glass plate 22 is provided with an opaque coating 22a of a uorescent material which has the ability to transform the ultra-violet rays into rays in the visible range. Coatings of this nature are well known in the art and may vary in their transmitted color from a blue to a reddish color. For example, the coating 22a may consist of a suspension of uorescent particles in a clear enamel Vehicle. Preferably, the coating 22a is applied to the surface of the glass plate 22 facing the ultraviolet tube 24 so as to eliminate any possibility of migration of the fluorescent material into the strips 20.

In the preferred embodiment of the invention, the strips 20 are of a shiplapped construction so that the individual strips may be aligned so as to provide a llush surface while still providing light-tight joints between the individual strips. As best illustrated in Figure 4, the strips 20 may be composed of a plurality of plies 31 of paper, the lami- 3 nated plies being impregnated with resin, as indicated at numeral 32 in the drawings. The front of the strip 20 as well as the side are given a coating of black paint 33 to help absorb any extraneous light.

The indicia on the strips 20 may take the form of engraved portions 34 which are cut suiciently deep into the paper plies 31 so as to be substantially translucent to the passage of light.

When the ultra-violet tube 24 is energized, the ultraviolet radiation which results is absorbed by the coating 22a on the glass plate 22 and transformed into light rays in the visible range. Inasrnuch as the coating 22a in itself is rather opaque, the coating serves the further function of `diffusing the resulting visible light uniformly throughout the glass plate 22 thereby providing, in effect, a uniform sheet of light behind the strips 20. The engraved portions 34 on the strips 20 being translucent are thereby highlighted against the black background provided by the non-engraved portions of the strips, giving rise to a very pleasing visual effect. It should be noted that the presence of the coated glass plate 22 serves the further important function of providing a backing for the strips 20, thereby preventing the strips from` warping upon changes in temperature.`

It will be evident that various modifications could be made to the described embodiment Without departing from the scope of the present invention.

We claim as our invention: l

1. An illuminated directory comprising a housing, a plurality of interengaged shiplapped strips providing a continuous face panel on said frame,each of said strips having a surface coating thereon preventing the passage of light therethrough, at least some of said strips being engraved beneath said surface coating to provide portions on said strips of greater light transmittability than the remainder of said strips, a source of ultra-violet radiation carried by said housing, and a glass plate pressing against the rear surfaces of said strips, said glass plate having an optically active surface coating thereon capable of transforming the ultra-violet radiations from said source into a diffused visible light.

2. An illuminated directory comprising a housing, a plurality of interengaged shiplapped strips providing a continuous front panel on said housing, each of said strips consisting of a laminate of resin impregnated paper plies, each of said strips having a surface coating thereon preventing the passage of light therethrough, at least some of said strips being engraved beneath said surface coating to provide portions on said strips of greater` light transniittability than the remainder of said strips, a source of ultra-violet radiation carried by said housing, and a glass plate pressing against the rear surfaces of said strips, said glass plate having an optically active surface coating thereon capable of transforming the ultra-violet radiations from said source into a diffused visible light.

References Cited in the tile of this patent UNITED STATES PATENTS 2,213,868 Lucian Sept. 3, 1940 2,275,934 Arbuckle Mar. l0, 1942 2,422,256 Phillippi June 17, 1947 2,561,813 Murphy July 24, 1951 2,594,903 Freedman et al Apr. 29, 1952 2,716,298 Spielmann et al. Aug. 30, 1955 2,768,460 Northrup Oct. 30, 1956 

